Pressure or flow regulation method for gaseous hydrogen dispensing system

Abstract

The present invention relates to a method for improving stability of a hydrogen gaseous dispensing system. An example of such system is hydrogen powered vehicle fuel filling station. Vehicle is filled by multiple high pressure gaseous hydrogen tubes, usually one tube at a time. For safety and reliability reasons a control requirement for such system is to be able to deliver the hydrogen at constant rate to the fuel tank so that its rate of pressure increase stays constant during entire filling process. A dual pressure regulator arrangement is proposed to better maintain flow continuity and/or pressure during tube switching.

The invention claimed is: 
     
       1. A system for adding a pressurized gas to a receptacle container that is fluidically connected thereto, the system comprising:
 a) a plurality of banks of pressurized gas containers, the banks each having a plurality of pressurized gas containers, wherein each pressurized container of a bank is fluidically connected to a common bank manifold and a common bank pressure control valve (PCV); 
 b) the common bank PCV being configured to be downstream from that bank, and all pressurized gas containers thereof, the common bank PCV adapted to control a flow of the pressurized gas from that bank to the receptacle container; 
 c) the bank PCVs configured and adapted to operate in sequence in response to a computer control; 
 d) the computer control configured and specifically programed to control the opening and closing of the bank PCVs in response to a pressure value representing a pressure of the pressurized gas in a first pressurized container of a first bank (Bank A), the computer control specifically programmed to execute the steps of:
 (A) detecting a first pressure in a first pressurized gas container of the first bank (Bank A), 
 (B) comparing the first pressure of the first pressurized gas container of the first bank (Bank A) to a receptacle container pressure, 
 (C) when the comparison of (B) reaches a pre-determined minimum pressure differential, comparing a pressure value for each pressurized gas containers of a second bank (Bank B) to identify a second pressurized gas container having the smallest pressure differential with the receptacle pressure container, 
 (D) opening a second isolation valve of the second pressurized gas container of the second bank to create a fluid communication between the second pressurized gas container and the second bank PCV, 
 (E) proportionally opening the second bank PCV to maintain a minimum pressure of the gas flow to the receptacle container based on a pressure decay of a pressurized gas flow through the first bank PCV, and 
 (F) when the first pressure of the first pressurized gas container falls to a second preset pressure differential with the pressure of the receptacle container, closing the first PCV. 
 
 
     
     
       2. The system of  claim 1 , further comprising (G) closing a first isolation valve of the first pressurized gas container concurrently with or subsequent to (F). 
     
     
       3. The system of  claim 1 , wherein the computer control is configured and specifically programed to additionally execute a set point swap process wherein a set point of the second PCV is set to a pre-determined value below the set point of the first PCV and then the pre-determined set point value is reduced to zero. 
     
     
       4. The system of  claim 1 , wherein the computer control is configured and specifically programed to repeat (A)-(F) for the second pressurized container and a third pressurized container in the first bank. 
     
     
       5. A method of adding a pressurized gas to a container that is fluidically connected to a pressurized gas delivery system in accordance with  claim 1 , the method comprising:
 a) detecting a first pressure in a first pressurized gas container of the first bank (Bank A); 
 b) comparing the first pressure of the first pressurized gas container of the first bank (Bank A) to a receptacle container pressure; 
 c) when the comparison of (B) reaches a pre-determined minimum pressure differential, comparing a pressure value for each pressurized gas containers of a second bank (Bank B) to identify a second pressurized gas container having the smallest pressure differential with the receptacle pressure container; 
 d) opening a second isolation valve of the second pressurized gas container of the second bank to create a fluid communication between the second pressurized gas container and the second bank PCV; 
 e) proportionally opening the second bank PCV to maintain a minimum pressure of the gas flow to the receptacle container based on a pressure decay of a pressurized gas flow through the first bank PCV; and 
 f) When the first pressure of the first pressurized gas container falls to a second preset pressure differential with the pressure of the receptacle container, closing the first PCV. 
 
     
     
       6. The method of  claim 5 , further comprising step g), closing a first isolation valve of the first pressurized gas container concurrently with or subsequent to step f). 
     
     
       7. The method of  claim 5 , further comprising a set point swap process wherein a set point of the second PCV is set to a pre-determined value below the set point of the first PCV and then the pre-determined set point value is reduced to zero. 
     
     
       8. The method of  claim 5 , further comprising repeating steps a)-f) for the second pressurized container and a third pressurized container in the first bank.